The present application is generally directed to a system for controlling access to a room. More particularly, the system may be used for controlling ingress to and/or egress from a restricted or dangerous premises that may be found in hospitals, medical facilities and other settings. The disclosed embodiments are particularly well suited for use with rooms used for Magnetic Resonance Imaging (“MRI”), where the system clearly communicates to those nearby that an MRI machine is in use and the room is off limits, and the system deploys a physical barrier to prevent entry into the room.
There are many activities and processes carried out in the health care, industrial, and commercial fields requiring that access to a room or area is restricted or prohibited. For example, in the health care field, such areas may include an MRI suite, an operating room in a hospital, X-Ray or CT scans (radiation exposure), infectious disease control rooms, or quarantined areas. Other examples where controlled access may be desired, include laboratories, clean rooms, manufacturing facilities, or areas where hazardous activities are taking place.
Prior efforts to control access to a room or area have included the posting of warning signs to warn people that access to a room or area is restricted or limited. However, warning signs located above doors have become commonplace and may easily be ignored. Another approach has been to simply close or lock the door to the room to prevent unauthorized access. However, shutting a door isolates the individuals working in the room from the rest of the building and provides a disadvantage of preventing communication between individuals within the room and individuals outside of the room. A locked chain or retractable belt across a doorway has also been used. However, where the room requires frequent egress and ingress, the locking and unlocking of the chain, or latching and unlatching of the retractable belt, becomes tedious, and as a result the chain may remain hanging, unlocked from the side of the door frame, and the belt may remain in its retracted state. Furthermore, with out-swinging style doors, a locked chain across the outside of the door will have the undesirable result of having the occupants locked inside the room.
A room having an MRI machine presents particular risks and challenges for warning and controlling access. An MRI scanner is a medical imaging technique that uses strong magnetic fields and radio waves to form images of the body. A superconducting magnet is used to create the strong magnetic fields required for imaging. However, the strong magnetic fields are also strong enough to pull ferrous objects, such as those containing, iron, cobalt, or nickel towards the superconducting magnet of the MRI scanner. Objects such as oxygen tanks, pens, scissors, screwdrivers, and other ferrous objects may be drawn towards the superconducting magnet of the MRI scanner at a high rate of speed and become a “projectile.” A projectile accident is defined as an occurrence where an object containing ferromagnetic material is pulled into the superconducting magnet at a high rate of speed.
Therefore, a dangerous situation exists during an MRI scan of a patient. In particular, if a person enters the room with a loose ferrous object during the scanning process, the patient and technologist administering the scan are in danger of being hit by a projectile being drawn towards the MRI scanner. It has been reported in the New England Journal of Medicine that large objects involved in projectile accidents have included an intravenous-drug pole, a toolbox, a sandbag containing metal filings, a vacuum cleaner, mop buckets, a defibrillator, and a wheelchair, among others. Five incidents involving oxygen or nitrous oxide tanks were also reported. Thus, it is known in the industry that MRI technologists and the patients they are imaging with an MRI scanning machine are subject to bodily injury or death resulting from the occurrence of a projectile accident.
In addition, the MRI magnet is always left on, and is not powered off after working hours. As a result, the potential for the MRI scanner to draw objects towards the magnet exists 24 hours a day. Cleaning personnel may not understand the potential for cleaning implements to become projectiles and possibly damage the expensive MRI scanning machines. As result, there have been instances reported of cleaning equipment such as floor cleaners, floor buffers, mop buckets, and the like being propelled towards the magnet of the MRI scanning machine, where damage to the MRI scanning machine may occur.
As noted above, it may be possible to lock the door to the MRI suite to prevent unauthorized access, or entry of someone having a ferromagnetic object, into the MRI suite. However, the door is typically kept open at certain times for a variety of clinical reasons including patient flow, medical staff egress and ingress, emergency situations to allow for simple communication with persons outside the room, and to allow the MRI technologist to monitor activity outside of the room. Metal detectors have been employed to prevent individuals having ferromagnetic objects from entering an MRI suite while a patient is undergoing an MRI scan. However, metal detectors may be highly sensitive and provide false alarms, both false-positive and false-negative alarms. For example, many women's bras include metal wires which can set off the metal detector. Repeated instances of false alarms may result in “alarm fatigue” and may cause the technologist operating the metal detector to be less vigilant, and overly casual when the metal detector alarm sounds thereby raising the potential that a ferromagnetic object could enter the MRI suite and cause a projectile accident.
As shown in FIG. 1, labeled as Prior Art, MRI suites are generally protected with passive signage, and in some instances, illuminated signs indicating the presence of a magnetic field. For example, as shown in FIG. 1, the standard signage may use a green illuminated sign 1 displaying various warnings directly over the doorway 2 of door 3. Most visitors or even facility staff members do not understand the danger of a projectile accident that may occur by someone entering the room where the high-intensity magnetic field is located. Other symbols on doors may be used, however, they do not convey the danger and are not sufficiently active to guarantee the attention of the viewer.
It would be desirable to provide a system that controls access to an MRI suite, to protect persons and equipment in the room by adequately warning that access to the MRI suite is prohibited, and by providing a physical barrier to entry to the room without entirely isolating the room.